Teen Wolf's Sunnydale Halloween
by onlymystory
Summary: A spell from the Alpha pack turns everyone into their Halloween costumes. Stiles has bigger problems though, as Derek got hit with a de-aging spell at the same time. Stiles has to juggle a scenting toddler, traumatizing behavior from his horny pack members, a killer Alpha and an ongoing debate over the best baseball team. But in the end it might be a Happy Halloween after all.


**I actually finished on Halloween! Barely but it still counts. I've had this wish to do a twist on the Buffy Halloween episode with Teen Wolf for a while, without being too horribly angsty. Adding in a de-aging Derek was my version of a perfect solution. Hopefully any mutual BtVS & TW fans don't hate me too much for screwing with a plot device to fit my purposes.**

* * *

"Halloween is a perfectly legitimate holiday, Derek Hale. Just because you get to be a creature of darkness every day does not mean that you are allowed to spoil my fun." Stiles had his hands on his hips as he glared at Derek.

The werewolf was insisting that the pack was not going to go trick or treating or to Halloween parties. Not him, not anyone. The others had given up the argument, though they were disappointed. As tended to be the case however, Stiles wasn't about to concede.

"Halloween is stupid," said Derek with a glower.

It looked more like a pout to Stiles and no, it was not cute. His brain needed to stop thinking stupid things like this.

"And it's dangerous. The Alphas are still out there," continued Derek.

"The Alpha pack can attack us here too. Besides, you're all werewolves. And a hunter. So I think we'll be just fine in a group. Can't you just trust me for once?"

"I don't trust anyone, Stiles."

"Yeah and don't we all know it."

Derek and Stiles both glared at each other until Derek gave in. "Fine. Have it your way. But I'm not dressing up."

"Fine."

"Fine."

"Holy shit, enough," snapped Lydia. "Look here's the deal, everyone find your costumes, then meet at the elementary school. They need volunteers to take the kids trick or treating. After that, Jackson's parents are out of town so we can finish the evening like normal high school students—and Derek—at his house."

The pack agreed and everyone left to get their costumes together.

As seemed appropriate, Derek was leaning against the porch rail outside Stiles' house when he emerged. And predictably, he was not wearing a costume.

"Be more lame," said Stiles, only a hint of sarcasm in his voice. It was Halloween. How does not one not dress up for Halloween?

Derek looked him up and down. Stiles was pretty sure it was just his brain fantasizing that said Derek's gaze lingered at his belt for a while. Stiles was wearing black jeans, black combat boots and his favorite red hoodie over a t-shirt. There was a long knife sheathed in his right boot, a few gadgets on his belt, and his favorite bat sat against his hip.

"Who are you supposed to be?" asked Derek.

"The badass version of Little Red Riding Hood."

Derek laughed.

"What?! The entire pack teases me all the time about being Red and the constant victim. I figured I'd play into it but change up the story a little bit. For once, Red isn't going to mean I'm the weakest one of the bunch." Stiles twirled his bat in what he hoped was a menacing fashion. It probably wasn't but at least he didn't drop it.

"You're not weak," muttered Derek.

"I'm…"

"Whatever," interrupted the Alpha. "Can we get this over with?"

"Fine, sourwolf. The kids will be so excited that you dressed up."

"I didn't have a costume and I wasn't going to spend money on one. Halloween is stupid, Stiles."

"Yeah, yeah, I've heard it before." Stiles' eyes lit up. "Hang on, I've got something." He hurried over to the jeep, tossing the bat and a small bag in the back before rummaging through the glove compartment. "I found this at a store the other day."

Stiles hands Derek a tiny replica of the Tardis on a chain.

"How is a Tardis necklace a costume?"

Stiles gapes at him. "You know what it is?! That's…that's…my world will never be the same."

Derek rolls his eyes at him.

"Anyway, you can wear it and pretend to be a Whovian for Halloween. Which apparently you are already. Not gonna get over that for a while just so you know. I mean, Derek Hale watches Doctor Who. This is amazing."

"If I wear the stupid thing will you shut up?"

"Sure," answered Stiles with a grin.

Derek slung the necklace over his head and followed Stiles to the car. Stiles tried talking to him again, even just to suggest he put his seatbelt on, but Derek kept glaring at him. Finally Stiles gave up.

A few blocks from the school however, there was a loud crack, then a flash of light, and Stiles slammed on the brakes.

Derek flew forward and hit the dash with a thump.

"Serves you right for not wearing your seatbelt," said Stiles without looking at Derek.

And then Derek let loose a piercing wail. Stiles whipped his head around to see a toddler of maybe four years old with the most unfortunate eyebrows ever sitting in his passenger seat. It was the eyebrows that reassured Stiles first that it was Derek, though the fact that Derek was wearing a miniature version of his current clothes helped too.

"Derek," said Stiles in disbelief. "What the fuck?!"

That clearly wasn't the right thing to say because Derek started crying harder, curling his legs up against himself and burying his face in his arms. Stiles quickly parked on the side of the road and pulled Derek into his lap.

"I'm sorry, I'm sorry, Derek. It's okay, you're okay," he crooned, rubbing the tiny werewolf's back. Stiles was kind of at a loss as to how to deal with this entire situation but he did know how to soothe a crying kid. One problem at a time.

"You're not my dad," sniffed Derek, wiping his eyes and looking up at Stiles.

"I'm Stiles," he answered the little boy. "I volunteered to take you trick or treating."

Derek's eyes went wide with excitement. "Really? I love Halloween."

"Of course this version of you does," muttered Stiles. He spoke louder to Derek, even though he was pretty sure the kid could hear him either way. "Yep. We've just got to get to the school. Though I think we'll walk so I don't end up killing us both if that light flashes again."

"But it's dark out," said Derek, a little bit of a tremble in his voice.

Stiles turned the wolf to face him. His gaze caught the necklace still around Derek and he wondered if that caused this de-aging. "Let's get this off you first," he said, tugging it away. "It doesn't really go with the costume."

Derek let him pull it away and then looked down at himself as though trying to figure out his costume. "Am I Wolerine?" he asked.

Stiles was a bit disappointed that taking the necklace off hadn't fixed the problem but like he did with most things that never went his way, he moved on. He took a tiny moment for a 'really?' at some unknown entity for the fact that toddler Derek knew about X-Men but mocked Stiles for his love of all things Marvel. Yes, Marvel. Batman was Stiles' only exception to the rule about which comic book verse had the best cast of characters.

"You sure are. But remember that you can't show your claws when other people are around," he warned.

"Can I do it really quickly?" asked Derek.

Stiles couldn't help giggling and told the toddler to go for it. Derek's claws flashed out and back again and he smiled happily. "It's still dark," he said with a wary look outside.

"I'll protect you," promised Stiles. "I won't let go, all the way to the school, okay?"

"Promise, 'Tiles?"

Mother of pearl. Stiles was going to melt in a puddle of goo by the time tonight was over. "Promise."

He got out of the car and lifted Derek up into his arms to head towards the school. The tiny werewolf wrapped his arms around Stiles' neck and held tight the entire way, only looking up when they walked under street lights.

Stiles couldn't help but think this might be his favorite Halloween. He reached the school to see Scott and Allison, though they were slightly obscured by Allison's car. Stiles hurried over to them only to scream and cover Derek's eyes as the two were definitely no longer fully in their costumes. Couldn't they at least use the car?

"Ugh, you guys, seriously cover up," he groaned.

"Who the hell are you?" growled Scott.

"Seriously?" Stiles looked at their costumes. "Grease? How are you two that lame with couples costumes?"

"What's his problem, Danny?" purred Allison and was her hair actually blonde? Oh yeah this was bad, Stiles.

"You're Sandy. And Danny Zuko right?" he clarified.

"Yeah. You gonna piss off now?" said Scott.

Stiles shuffled Derek around to his hip and walked away, muttering about ingrates and that clearly traumatizing Stiles is popular in any decade. At least they weren't likely to harm anyone.

He didn't see any of the others and it looked like most of the kids had already left with other volunteers so Stiles took a minute to sit on a bench outside the front doors. He tried setting Derek next to him but the werewolf just crawled back onto his lap. Stiles wasn't all that upset.

They were sitting quietly as Stiles tried to think. This had to be the work of a witch but he needed to figure out why and who all it affected and then how to break it. Also, the whole thing was annoyingly familiar. Like seriously, didn't witches have any sense of originality?

Derek squeaked when a shadow loomed over them. Stiles looked up to see Ethan, one of the alpha pack members standing in front of him. It took him all of seven seconds to stand up, shove Derek behind him, and yank his knife out of his boot. "You." He said, knowing exactly who was behind the spell now.

"I'm not here to hurt you, Stiles," said Ethan quickly.

Stiles gave him a disbelieving look.

"I'm here to warn you. This was Kali's idea and I like a fair fight." He wrinkled his nose disdainfully. "Using a spell is a cheater's way to victory."

"So it is a spell. That explains why Scott and Allison turned into their costumes. Though it doesn't explain…" he stopped before revealing that the toddler who was currently hiding his face against the small of Stiles' back was actually Derek Hale.

"Isn't that an episode of Buffy?" asked Ethan, eyebrows crinkling.

"Yes! Thank you," said Stiles. "I thought I'd never find someone who appreciated quality television and wait, why the hell am I trying to bond with a guy who wants to kill me, this is absurd."

"I don't want to kill you," interrupted Ethan.

Stiles gave him a questioning look that somehow also managed to convey a don't even try to bullshit me right now tone. Stiles would take the time to be proud of himself later.

Ethan huffed. "I don't. Everyone else does but I find you fascinating."

"That is potentially the creepiest compliment I have ever heard and I regularly spend time with Derek Hale," returned Stiles.

"You just smell so…" Ethan's voice trailed off and he leaned in close to Stiles and sniffed at the teen's neck.

Before Stiles could step back and push the alpha out of his way, Derek was snapping his teeth and growling at the other werewolf.

"Derek!" yelped Stiles, surprised at the baby werewolf. And shit, there went hiding that secret.

"My Tiles," growled Derek in a far too adorable voice for Stiles to properly deal with.

Ethan pulled away from Stiles and smiled indulgently at the toddler. "I think we could figure out how to share, Derek."

Derek slapped Ethan.

"No!" Stiles yanked Derek's hand back before Ethan could decide to be less calm and tear the toddler's head off and pulled the toddler into his arms. "We don't hit people."

Derek buried his head in Stiles' shoulder and started crying. "Tiles hates me."

"Oh for the love of god," muttered Stiles. He used his free hand to slowly pet Derek's head, smoothing out the dark curls and whispered softly to him. "It's okay Derek. I don't hate you, sweetie. But it's not nice to hit people, okay?"

"Okay," sniffled Derek and his arms clenched tight around Stiles' neck. A few seconds later, Derek started licking at Stiles' neck.

"Derek, what are you doing now?" asked Stiles, doing his very best not to sound upset or angry with the four year old.

Derek licked his neck, then ran a tiny hand over the spot, then licked again. "You smell funny. I's fixing it." He kept repeating his tiny ministrations, muttering "I fix it, Tiles," as he worked.

Stiles sat down on the bench, not even caring that he had to look up to Ethan now. The alpha was watching the two of them with a puzzled look on his face. "What?" asked Stiles.

"He's scenting you," said Ethan.

"So? I thought that was a thing with you guys. And he's four, I'm not going to yell at a four year old for not realizing he can scent someone without using his tongue." Stiles glared at the Alpha.

"Not what I meant." Ethan shook off his current train of thought. "I just wanted you to know that Aiden and I won't be a problem tonight. We like a fair fight and we won't be attacking the pack. You're clearly the only one in a position to deal with that."

"Why is Derek the only one turning younger?"

"I don't know. That wasn't part of her spell. It was just supposed to turn all of you into your costumes, essentially taking away the werewolf powers, hunter, and research skills. It'll end in a few hours. Or sooner if she can find Derek first."

"But I didn't turn into my costume," argued Stiles.

"Who are you supposed to be?" asked Ethan. He smiled a little when Derek shifted to the other side of Stiles' neck.

"It was supposed to be ironic. Badass version of Red Riding Hood."

Ethan gave him an intrigued look. "Did you ever consider that maybe you already are that?"

Hmm. No, Stiles hadn't. He would now though. Interesting.

"Since you say you want to play fair, any idea what's going on with Derek?" he asked.

Ethan pondered Derek for a moment. "I'd say a standard de-aging spell. It'll probably wear off about the same time as the other one. Do you know what triggered it?"

Stiles shrugged. "He was wearing a Tardis charm. I wondered but it didn't change when I took it off him."

"It wouldn't. Once a de-aging spell is activated it has to run its course. The container for the charm is usually important though so I would guess that you'll see a couple other versions of Derek before it ends."

"Why would the spell affect Derek and not me? I wore the necklace the other day."

"Either the spell recognized something in Derek that needed to experience this or it was triggered by Kali's spell," answered Ethan. "Or possibly both. I've got to get back to Aiden. Even you aren't worth dealing with Kali if she sees me here. You understand I won't harm you tonight?"

"And Kali?" asked Stiles.

"Kali is a threat to you."

"I won't let her hurt Derek," snapped Stiles. "Is that going to be an issue later on?"

"No," said Ethan. "Her choices, her consequences." Then he turned on his heel and left with a final puzzled glance at Stiles and Derek.

Derek was fading again, starting to fall back asleep. Stiles hefted him up again and started walking. He needed to figure out what was going on with the rest of the pack and get some provisions out of his jeep.

By the time Stiles retrieved his bat and newly invented but yet to be tested wolfsbane spray, he'd managed to track down Lydia, Isaac, and Danny.

Lydia had chosen to be a specter for Halloween and her now phantom self gleefully informed Stiles that she was trying to find Peter so she could haunt him for a few hours. Stiles may have given her Peter's address but he was so denying it whenever this got fixed.

Isaac and Danny had both chosen to go as Rat Pack vampires, which Stiles hadn't been sure was a thing. There had been a minor moment when Danny lunged at him from the shadows, because of course Stiles still looked like dinner.

Stiles had gripped a sleeping Derek tighter and prepared to fight Danny off. How he'd been going to do that was a good question. In the end, Stiles hadn't needed to worry. Danny took one whiff of Stiles and started gagging and complaining about the smell of dog.

Which, hello, rude.

A few seconds later, Isaac and Danny were making out against the wall in the alley so Stiles figured it was time to go. His pack was ridiculous.

He made it almost to the local coffee shop, where he figured he'd just sit and let Derek sleep until the spell wore off. Or Kali found them but he was trying to think positively. A few yards away, but thankfully still in the dark, Stiles stumbled as the toddler into his arms suddenly shifted into a nine year old.

"Who the hell are you?!" yelled the kid as he fell to the ground.

Stiles pushed himself back up and swore. "Don't swear, Derek. It's rude."

Derek apologized so quickly it nearly gave Stiles whiplash. This may still be the Alpha but he kept reacting like the beta he thought he was.

"I'm Stiles. I got stuck on Derek duty for Halloween," he answered, trying to word things carefully enough to disguise a lie.

Derek looked at himself. "Guessing I'm supposed to be Logan, huh?"

Stiles nodded. And told himself that Derek was not getting out of marathoning X-Men, even X2 once he was back to his adult self.

"Why don't we have candy?"

"It's in the jeep," said Stiles, thankful he had actually tossed a bag in there when he left the house. "But I wanted coffee so we're stopping here first."

"Can I have coffee?" asked Derek. "Laura says I'm too young but I don't think so. Sometimes dad lets me drink his and I like it."

Stiles tried not to let the way his heart clenched at those carefree words show on his face. "Sure. But mostly decaf."

Derek agreed to that compromise and claimed the two comfy chairs in the corner while Stiles ordered.

Whereas toddler Derek had stuck around for nearly two hours, nine year old Derek was only around through their cups of coffee. But Stiles got to learn a lot. He found out that Laura was fighting to get a girls' lacrosse team at school (still hadn't happened) and that when she wasn't bossing Derek around, Derek thought she was the second coolest person ever.

The coolest being Wolverine. Obviously.

Derek liked snickerdoodle cookies and thought having a birthday in March was totally boring because nothing good ever happened in March. Natalie was lucky to have a birthday in the summer because she always got to go to the water park.

The baseball debate got a little prickly as Derek adamantly argued that the Dodgers were the best team in baseball. Stiles managed to save it from being an all out fight, because damn it, the kid was wrong, by turning it to a discussion of what positions they both played (left field), when a light flashed again and a sixteen year old Derek sat across from him.

Stiles felt lucky that the barista had been in the back and they were the only ones in the room. She didn't even give him a puzzled look when she returned, probably figuring the kid had been picked up and that one of Stiles' friends met him here.

The teenage Derek stared at Stiles. "Who are you? How did I get here?"

"Ugh," muttered Stiles, thinking quickly. "I'm Stiles. I go to Beacon Hills too and you seemed kind of out of it so I brought you in here until you felt better. Which I'm guessing is now."

"Alright," accepted Derek.

Stiles was starting to wonder if the kid just trusted everything people told him. The fire must have really done a number on Derek to make him so distrusting now.

"Mind giving me a ride home?" asked Derek, startling Stiles out of his reverie.

"Yeah sure," answered Stiles. He had the feeling this version was going to be around even less than the last. "We'll have to walk though. I'm parked a few blocks away from the school."

"That's cool," said Derek.

They walked in silence for a minute and then Stiles couldn't resist prying. He thought Derek was interested in him sometimes, or at least attracted but neither had ever done anything about it. Asking Derek if he was dating anybody was totally innocent.

It took Stiles about three minutes to realize how completely wrong he was.

"You got a girlfriend?" he asked, in his most subtle voice. "Or boyfriend? Not judging."

Derek hesitated.

"You do!" crowed Stiles. "C'mon, tell me about her. I'm single so living vicariously through others is all I've got."

"You can't say a word to anyone," demanded Derek.

"Scout's honor," said Stiles.

"She's older than me so she doesn't want me to tell my parents about her," said Derek.

"Cougar got a name?" laughed Stiles. He figured Derek hadn't been offended by the boyfriend comment so he was holding on to a little hope.

Derek stopped and leaned against the street light, a ridiculously dreamy look in his eyes. "Kate Argent."

Stiles wanted to throw up. Fuck. He was an asshole. Not to this Derek obviously but his Derek was going to kill him. And let's not consider that he just said his Derek.

But oh man, did this explain a whole hell of a lot. Stiles was seriously tempted to go dig up Kate Argent's grave just so he could rip her body to pieces. That selfish, psychotic bitch!

Derek continued as though Stiles wasn't having a meltdown. "I'm totally in love with her. I know it seems stupid, like I'm sixteen, I shouldn't know what love is. But I do. She's the best thing that ever happened to me."

Stiles was pretty sure he was going to start crying in the middle of Oak Drive. He swallowed hard and started walking again, trying to ignore Derek as he extolled the virtues of the woman who would be burning his family alive in a few short weeks.

Fucking bitch, thought Stiles again. His Derek was right. Halloween sucked.

As they turned onto the street that the jeep was on, Stiles switched the subject by declaring the Mets to be amazing, figuring Derek would still be into baseball and follow the distraction.

It worked and Stiles breathed a sigh of relief.

Stiles laughed at Derek's argument for why the Dodgers were better than the Mets when there was a loud crackling sound. He turned to see Derek shift into his current 24 year old form before collapsing onto the ground. Stiles started to bend down and check on him when he felt the sense that someone was watching him.

Kali was moving up the dark street, eyes red in the night. She was already partly shifted.

He picked his bat up from the floorboard of the jeep and moved around to keep her from Derek. She wasn't getting his alpha. Not today. Not ever. Screw her and her plans.

Stiles stood in the street facing Kali, bat at his side. "I wondered when you would show up."

"You're supposed to be unconscious," snarled the Alpha.

"I've never been one to follow the rules," returned Stiles. "You can't have him."

"You're going to stop me? A pathetic teenage boy?" Kali laughed at him and stepped closer.

Stiles twisted the bat in his hands and realized in that moment that he wasn't weak because he was human. It occurred that this sort of epiphany was slightly cheesy but he knew in that moment that he was going to beat her. Not necessarily because he was so much stronger or had some bizarre power.

No, he would win because he fought to keep the people he loved. And Derek was absolutely one of those people. So Kali could take her threats and her desires for power and shove them up her ass. Stiles wasn't in the mood.

"Yes," he said simply in answer to her question and raised his bat in the air.

"That spell is going to wear off you any minute now and then what happens, Little Red? I could tell you about all the ways I'm going to rip you to shreds once it's just you."

Stiles smirked. "Seeing as I've pretty much been living out one of my all time favorite television episodes, allow me to clue you in. I don't need a 'daddy's home' moment because I never left. Now back. The. Fuck. Off."

Kali leaped at him.

Stiles swung the bat into her face.

The werewolf howled as the wolfsbane that Stiles had sprayed onto the bat earlier burned against her skin. Her next attack was uncontrolled, wanting revenge, so Stiles was able to slam the bat against her left leg, then Kali's right arm when she bent over in agony.

They kept fighting and Stiles staggered back against the jeep at one point when Kali's claws swiped through his hoodie and into his ribs.

He came back swinging harder after that.

A good fifteen minutes later, Kali was dead on the ground, a wolfbane soaked knife in her heart and Stiles was breathing heavily and leaning on his bat to keep from falling over.

He used his first aid kit from the car to patch up the claw marks first. Derek still hadn't woken up yet and Stiles wanted to get him home instead of letting him wake up here.

Stiles decided that it would be best to let the pack clean up the mess. They'd started texting him, trying to figure out what happened. He promised to explain later, saying he was with Derek and everything would be fine.

Once Stiles sent a detailed text to the rest of the pack and got their reassurance that they would take care of Kali before meeting up later, he managed to get Derek into his jeep and eventually stumble into the house and get Derek on the couch.

It took about ten more minutes for Derek to wake up and he looked confused at first and then worried. "What happened?"

"A double dose of spells," answered Stiles. "One that didn't really affect you and another that de-aged then re-aged you. It was some weird twist on time travel that I don't exactly understand."

"How old did I become?"

"Four, nine, and sixteen." Stiles knew it was the last one that was going to be the issue for Derek. Derek would be wondering what he'd told Stiles, if he'd said anything, if he'd given away too much to the pack. Stiles waited.

Derek was quiet for a long time, but he didn't get up or leave or run away and that was more than Stiles had hoped for.

"Do you remember anything?" asked Stiles when the silence got to be too much.

Derek shook his head. "Not really. Just…just you."

"Well I was the one with you the whole time."

"No, it feels different. I don't know how to describe it," said Derek and he sounded frustrated, like he should be able to figure this out.

There was another long pause. "What did I say?" asked Derek, and he sounded so scared and nervous that Stiles had to sit on his hands to keep from pulling the werewolf into his lap like Derek was back to being four years old.

"You called me Tiles a lot as a baby and slapped Ethan," began Stiles.

Derek's head snapped up for a second. "Ethan? The Alpha? Did he hurt you because of me?"

"No. No Derek," said Stiles quickly, hoping his tone was reassuring. "He just kept giving you funny looks and then you started scenting my neck."

Derek's eyes went wide but he stayed quiet. "What else?"

"You told me a lot about Emma and Ella, I figured those were the twins, and made sure I understood that the Dodgers were the best team in baseball."

"It's true," interrupted Derek.

"It's a bald-faced lie," retorted Stiles. "Even nine year old you with better puppy dog eyes than Scott is not going to convince me to abandon my Mets. You told me some little details, like your birthday and favorite foods, and apparently you thought Laura walked on water as a kid. Your sixteen year old self wasn't as big of a fan of the big sister though."

Stiles stopped then because he hadn't really liked dealing with sixteen year old Derek. He'd learned more than…not more than he needed to know about Derek, but definitely more than Derek would ever be comfortable sharing.

Derek seemed to guess what he wasn't saying. "Did I tell you about…?"

Stiles nodded. "Yeah."

"Do you hate me now?" asked Derek in a quiet voice. Too quiet.

"No!" Stiles didn't hesitate. He didn't have to. He could never hate Derek.

"Why not?" asked Derek miserably. "I hate myself. You should hate me too." He wasn't even looking at Stiles now and that just wasn't going to work for Stiles.

"Derek, look at me."

Derek kept his head down and flinched away from Stiles.

He didn't think he could manage to pull Derek to him, so Stiles threw self-preservation out the window and flung himself onto Derek's lap. Stiles used two fingers to lift Derek's chin up, forcing the werewolf to look him in the eyes.

"I could never hate you, Derek." Stiles tried to think of what to say next and decided to go with honesty, hoping it would stop the tears he could see in Derek's eyes. "I hate her. I've spent almost a year being quite happy that Kate Argent is dead but tonight, for the first time, I wanted her to still be alive so I could kill her myself for hurting you like that."

Derek blinked furiously at Stiles, trying to comprehend exactly what he was saying.

"You were so happy and trusting," said Stiles, starting to cry a little. "And I hate her for turning you into this man who doesn't know how to trust anyone anymore."

"I trust you," breathed Derek.

Stiles froze. "You do?"

Derek reached a hand up and ran it along Stiles' cheek. "You protect me," he whispered. "You're always saving me and fighting for the pack even though you're so…"

A few hours ago Stiles would have filled in the blanks with something like "weak, human, fragile". But that was before. Before he'd learned that it wasn't so much that he couldn't fight at the level of a werewolf. It just took more to get him to that level. Which wasn't a bad thing.

"Much better than us," finished Derek. "You're strong. The pack…" His voice faded, then got stronger. "I don't deserve you."

Stiles gave in to his own needs and desires for the briefest second as he leaned forward and pressed a kiss to Derek's lips. "You deserve what makes you happy," he said, pulling back so he could look Derek in the eyes again. "Whatever that is."

Derek's hand cupped the back of Stiles' neck and tugged him back down. "You make me happy."

Derek kissed Stiles this time, a little more forcefully, but still tentative, like he thought Stiles would still run away. Stiles just wrapped his hands around the edges of Derek's jacket and pulled himself in closer. The werewolf tasted like sage and pine and something uniquely Derek. Stiles was fairly certain he could spend hours trying to figure out what that taste was.

In return, Derek pushed his tongue against Stiles' lips, licking and gently biting to get the teen to open up. Stiles was cinnamon and old books and Derek needed as much as he could get.

They kissed for long moments until Stiles moved his lips away from Derek's and buried his face in Derek's shoulder. He mumbled into Derek's neck words that were indecipherable but there was a smile with them. The Alpha chose to simply rub his hands up and down Stiles' back, offering what comfort he could.

Derek's hands stilled when he brushed Stiles' right side and Stiles cringed.

"You're hurt," said Derek.

"Its fine," said Stiles, not moving.

"Let me see," demanded Derek, though his voice was gentle.

Stiles leaned back and shrugged off his hoodie before letting Derek pull his shirt over his head. The claw marks that Kali had left were scabbing over but still raw and red. A car's first aid kit didn't do a lot of good.

"What happened?"

"Kali," answered Stiles.

"How did you get away?" asked Derek, and if his voice had a growl in it that someone had hurt Stiles, his Stiles, he wasn't apologizing for it.

"I didn't," said Stiles. "Kali's dead."

"How?!"

"I killed her." Like it was as simple as that. And really, in the moment it had been.

Derek's eyes were wide. "I thought you dressed up as a badass version of Little Red Riding Hood? Which still makes no sense to me. Does she come with ninja powers or something?"

"What happened to I'm strong and amazing?" huffed Stiles in mock indignation.

"All still true but Stiles, we're talking about the Alpha of alphas."

"Ninja powers?" Stiles had only just registered that part of the conversation. "Seriously, Derek?"

"I don't know," he grumbled. "You killed an alpha. I just wanted to know how."

Stiles grinned. "She was the one who got a witch to cast the spell that made everyone their costumes. It was supposed to last for several hours and knock everyone out once it was over. Kali meant to find you during the spell to take you out and then take down the rest of us while we were out of it. But the spell in that Tardis charm meant she couldn't track you down as easily. Especially after Ethan warned me what she was doing."

Derek pouted the tiniest bit. "Ethan likes you."

"Yep," agreed Stiles. "But I like you so it doesn't matter." He ducked his head to kiss Derek's nose before dodging away. "Anyway, Kali tried to attack you but she didn't realize that I wasn't affected by the spell."

"Why didn't the spell affect you?"

"Without being annoyingly philosophical because I refuse to ever act like a Psych 101 student, especially after Scott and I did that college tour last fall, I think because I was already a badass. The only one who didn't realize I was strong enough to fight was me."

Derek indicated for him to keep going. The werewolf moved his head along Stiles' side and licked at the wound, helping it heal.

Stiles shivered a little at the touch, in the best way possible, and continued. "So I beat the crap out of her with a baseball bat and then I stabbed her in the heart with a knife soaked in wolfsbane."

Derek kept licking him and Stiles could feel the claw marks healing. "I like _ you're _ ass."

Stiles could only make out half of what Derek said since he wouldn't stop moving his tongue. Which he distinctly noted was no longer on the claw marks but was steadily moving towards his hips. "Did you just say you like my ass?!" He laughed a little.

"I said I like that you're kind of badass," said Derek, growling at him in that Stiles' stop teasing voice.

"Oh," said Stiles, pretending to be upset.

Derek pulled back a little bit and looked at Stiles again. "Do you want me to tell you how much I like your ass too?"

Stiles ground his hips against Derek the slightest bit. "I'm really more of a sensory learner…"

Derek's hands slid down Stiles' back. "I can work with that." He kissed Stiles again, a little bit filthier than the kisses were before.

"Happy Halloween," Derek whispered.

Stiles grinned. Happy Halloween indeed.


End file.
